Two months ago I started training for the Sydney half marathon. About one month ago I stopped. And now I’m with 11,000 other mugs ready to tackle the race.

I start in the Yellow group, the last group. Looking at my rivals I’m not worried about being able to complete the run. This is not an elite group. There is a lot of flesh bursting out of Skins.

The race announcer is a mumbled voice talking to the front group. We don’t hear a starter’s gun at 6.45. We just shuffle forward, nearing the start line, then find ourselves in the race at around 7.

“Anyone’s birthday today?” asks the announcer as we cross the start line. Few hands are raised as people look for an open run. “Anyone divorced today,” he asks, and gets less response.

It’s an easy run past St Mary’s Cathedral then down to the Rocks. The porters out the front of the Park Hyatt give us a clap before we pass under the Harbour Bridge.

It’s interesting to run along Barangaroo and see what the site is like without James Packer’s dirty great casino there. It would be a nice jog through the city if my left knee wasn’t already aching.

For a moment I fear my knee is going to give away under me. I take it slow and try to run smoothly. It’d be a bit embarrassing to drop out before five kilometres.

I have heard of “runner’s high,” where the flood of endorphins leaves a runner blissed out and oblivious to pain. I suspect I’ve skipped past it, straight to runner’s comedown. For the bulk of the run I wonder why the hell I’m even bothering. What am I trying to prove? What’s the point of it all? Though maybe this is runner’s high. These are the same questions I ask after a joint.

At the drink stations I slow to the walk. Jogging past the portaloos, I envy the people who get to have a break as they wait to take a shit. The kilometres tick by. My knee stops hurting once my legs go numb.

I look ahead for people who are fatter than me and challenge myself to pass them. I’m caught up in the run. I’m going to finish.

It’s a cruel course that makes you run past people crossing the finish line then takes you on a left turn for a four kilometre slog past the Art Gallery to Mrs Macquarie’s Chair and back. On the final two kilometres I consider going all out. My lungs are fine, I’m not even puffing. My legs, on the other hand, aren’t running with my body. I plod on. I’m not going to break any records.

I cross the finish line at an unremarkable 1 hour 55 minutes and raise my hands in victory (though I’ve come 5,555th). I slow to a walk and my legs race forward like I’ve stepped on a travelator. They aren’t ready to stop.

It’s a few minutes until the pain settles in. I hobble past other competitors feeling dazed. It’s pointless and proves nothing but after completing the half marathon I feel pretty happy with myself. Completely rooted, but happy.

On a narrow street in Newtown a giant dog towers above the traffic. Passers-by double take at the massive sculpture. Cars slow down as they pass the trailer it sits on, and come to a stop as drivers stare.

The Sydney sold in tourism ads is one of golden beaches, blue skies and a sparkling harbour. In a series of noirish photographs Christian Ferreiro, a graphic designer, has captured an altogether different place.